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rec.pets.dogs: Genetic Diseases in Dogs FAQ


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Archive-name: dogs-faq/medical-info/genetic-diseases
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Last-modified: 07 Nov 1997

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                   Eliminating Genetic Diseases in Dogs:
                           A Buyer's Perspective
                                      
                                    Author
                                       
   by Gary F. Mason, gmason@ileaf.com.
   
   Copyright 1995 Gary F. Mason. All rights reserved. However, you are
   encouraged to copy and distribute this article for non-commercial use
   with the following restrictions: You may not modify the article in any
   way. You must include the entire article including the copyright
   notice. You may not charge any fee for use, copying, nor distribution
   of the product with the following exceptions: Non-profit organizations
   may charge a nominal fee (not to exceed $5.00) until and unless
   notified by the author this is not the case.
     _________________________________________________________________
                                      
   _QUICK INDEX: : _Introduction, Goal of the Effort , Scope of the
   Effort , Description of the problem , Technical Obstacles , The Human
   Component , An Approach to the Problem , Basic Education, Genetic
   Information Sharing , Preregistration Testing , Show Validation ,
   Modification of Breed Standards , Registration Organizations , Health
   Related Organizations , Conclusion , Selected References ,
     _________________________________________________________________
                                      
Introduction

   This paper is the first product of an effort I have undertaken that
   was prompted by the discovery that our five month old Scottish Terrier
   suffered from Type III von Willebrand's Disease (vWD). The existence
   of this genetic bleeding disorder was unknown to us until he suffered
   a near fatal bleeding episode for no apparent reason. Subsequent
   treatment and testing revealed that he was affected with vWD.
   
   We were quite naive - as I suspect many people are - when we bought
   our dog. Both of his parents were AKC registered, which we assumed
   meant that he was a healthy dog from healthy stock. In fact, prior to
   discovering his affliction, he too was registered (though we could
   have registered him even after discovering his malady). We have
   learned the hard way that "having papers" means very little, if
   anything, about the genetic health of a purebred dog.
   
   This experience convinced us that dogs, and those who own them, should
   not have to live under the conditions dictated by genetic diseases.
   This is especially true since in the main they could be prevented. Our
   dog's disease has generated a lot of additional expense and worry
   which might have been avoided by a properly designed and managed
   breeding program. It has also become clear to us that prospective
   buyers should be better educated about the world of dogs before they
   make an investment that could lead to considerable extra expense, and
   worse, the heartbreak of losing a beloved friend too early.
   
   This effort has no funding or sponsorship from any organization or
   other individuals. We neither breed nor show dogs, and have no plans
   to do so in the future. This is a personal attempt to contribute to
   the identification of, the development of tests for, and the progress
   of efforts toward the eradication of genetic diseases in dogs.
   
   This article is intended to be an objective exposition on the subject
   of genetic diseases in domestic dogs. It is of the utmost importance
   that the information presented be as neutral as possible so as to
   encourage all interested parties to engage in productive dialog. No
   attempt will be made to attach any measure of goodness or
   acceptability to one view of an issue over another. It is hoped that
   this approach will enable synergies to be created by joint activity
   among and between parties interested in improving canine genetic
   health.
   
   While no one is intentionally being eliminated from the target
   audience, the specific constituencies being addressed are breeders,
   breed clubs, dog registration organizations, prospective dog
   purchasers, researchers, and veterinarians.
     _________________________________________________________________
                                      
Goal of the Effort

   The goal of this effort is to provide assistance to any and all
   concerned parties in hopes of making progress toward the elimination
   of genetic diseases in dogs, and to generate additional interest in
   that effort. To that end, it is intended to:
   
   Educate the audience on the subject of genetic diseases in dogs.
   Present a brief summary of some of the research and other activities
   currently underway which are working toward the elimination of genetic
   diseases in dogs. Suggest some options and approaches which can be
   examined with regard to their effectiveness in reaching this goal, in
   both the short term and the long term. Foster open dialog and
   cooperation among and between all interested parties.
     _________________________________________________________________
                                      
Scope of the Effort

   Although primarily terrier breeds are referenced here, this effort is
   not limited to any specific diseases or breeds. On the contrary, it is
   intended to encompass the widest range of both. It is hoped that in
   this way, the largest possible group of people will be induced to
   participate, and the broadest view of the subject will be developed.
   
   This document is a first step, and proposes to use Type III von
   Willebrand's Disease in the Scottish Terrier as the example around
   which to build a framework for further efforts. The current level of
   knowledge about this disease is extensive, and indicates that this
   disease, in this breed, presents one of the simplest cases of genetic
   disease in the dog. Even if this proves to be true, vWD still offers a
   formidable set of challenges to the community committed to its
   eradication. But as a relatively simple example, it provides the
   opportunity to"start small". The framework developed for attacking vWD
   could be used as the starting point for more elaborate requirements
   which would be dictated by more complex diseases.
     _________________________________________________________________
                                      
Description of the problem

   Many diseases in the domestic dog are genetic in origin. Examples are
   vWD, Collie Eye Anomaly, portosystemic shunt, hemophilia, Scottie
   Cramp, hip dysplasia, Legg/Calv Perthes, medial patellar luxation, and
   craniomandibular osteopathy (CMO) -- the list is very long. So far,
   over five hundred genetic diseases have been identified in purebred
   dogs, and over a hundred in mixed breeds. They can affect
   conformation, health (virtually all systems in the body are subject),
   and temperament. In Scotties alone there are 36 identified genetic
   diseases, with similar numbers affecting each of several other terrier
   breeds.
   
   There is a great deal of scientific research being performed on the
   identification of the specific causes of genetic diseases. Because
   some of the diseases exhibited by dogs are also evident in humans --
   vWD is the most common human inherited blood disease -- some benefit
   could derive from canine research which would be of use in pursuing
   the human form of the same, or related, diseases.
     _________________________________________________________________
                                      
Technical Obstacles

   "There are no more easy problems." Anonymous
   
   The need for accurate definition of the mode of inheritance - The
   underlying causes of genetic diseases can be very complex. Efforts are
   underway to identify and isolate specific genes, and combinations of
   genes, related to various diseases. But it will probably be a very
   long time before most have been isolated. The research process is
   costly and very time consuming.
   
   Variation in the expression of the disease - Genetic diseases which
   appear to be identical across breeds may in fact be caused by
   different genetic conditions. For example, vWD is believed to
   exemplify one mode of inheritance in Scottish Terriers, and another in
   German Shorthaired Pointers.
   
   The absence of accurate tests - Some genetic characteristics can be
   determined by observation, but more frequently tests are necessary to
   identify specific genetic diseases. There are currently two tests for
   vWD, one more recent (and accurate) than the other. They test for the
   same constituent in the blood, but use different testing techniques.
   These tests are based upon measuring the quantity of a specific
   chemical in the blood, and while the test itself is very good, the
   results are subject to substantial variation based upon the collection
   and handling of the test samples. And there can be major variations in
   the amount of the chemical present in the animal due to its condition
   at the time of sample collection. Other genetic diseases depend upon
   other methods for their diagnosis. These include X-ray, physical
   manipulation, and other techniques. Testing for recognized genetic
   markers, or the genes themselves, will offer a virtually foolproof
   method for diagnosis. When a definitive test is developed for any
   disease, there should be no reason to ever produce a puppy adversely
   affected by that disease.
     _________________________________________________________________
                                      
The Human Component

   Any attempt to address the genetic disease problem in dogs must take
   into account the human component. People breed dogs for many reasons.
   While there are exceptions to every rule, most breeders of pedigreed
   dogs do seem to have the animals' best interests at heart. In the
   main, the production of dogs with genetic diseases today is not done
   out of malice, but out of ignorance due to a of lack of historical
   genetic information.
   
   But there are other forces at work as well. Many dogs are shown at
   events sanctioned by various registration groups. Breeders of winning
   dogs earn the respect of their peers and others, and that respect can
   lead to enhanced benefits to the breeders. Within this environment,
   other benefits can also be accrued from breeding winning dogs. These
   include improving the breed; gaining personal satisfaction; and
   commanding higher prices for puppies bred from the winner's
   bloodlines.
   
   For genetic diseases to be eliminated, they should be given at least
   as much weight as the other factors considered when breeding a dog --
   principally conformation and behavioral traits. For any plan to be
   successful would probably require that these benefits remain
   achievable at current rates or better. The incentives provided for the
   breeding of dogs without genetic diseases should be at least as good
   -- probably better -- than exist today.
     _________________________________________________________________
                                      
An Approach to the Problem

   Since genetic diseases are passed to subsequent generations by parents
   who contribute the causal factors contained within their own genetic
   makeup, one point regarding this problem is fundamental:
   
   The elimination of genetic diseases can only be accomplished through
   selective breeding
   
   The problems lie in determining how to identify the diseases' causal
   factors in dogs; in understanding when not to breed them; and in the
   implementation of selective breeding programs based upon these
   factors. Some of the avenues to be investigated include:
     _________________________________________________________________
                                      
Basic Education

   First and foremost in solving any problem is ensuring that everyone
   involved understands it. While genetics can be a very complex
   technical subject, the basic information required to make progress
   toward the elimination of genetic disease by developing an effective
   breeding program is within the reach and understanding of everyone
   concerned.
   
   Breeders should understand the implications of genetic diseases
   recognized as affecting their breeds, and take steps to breed only
   those dogs that will minimize the propagation of unwanted
   characteristics.
   
   Prospective buyers should be made aware of the genetic diseases
   related to the breed they are considering. And they should learn to
   ask that test results or genetic histories for the animals they are
   planning to purchase be explained to them.
   
   Veterinarians should be able to recognize genetic diseases, and inform
   owners, breeders, and prospective breeders of their presence in dogs
   they examine and treat.
   
   A general information publication on genetic diseases in all dogs
   could be prepared. A cooperative effort among many breed clubs and
   other interested organizations could reduce cost and gain maximum
   exposure for such a product. By crossing many breeds, a single
   publication could be offered to the public at many venues, including
   shows for single and multiple breeds, county and state fairs, and
   other events at which those interested in dogs might be expected to
   attend. There are many opportunities to spread the word.
     _________________________________________________________________
                                      
Genetic Information Sharing

   Dog breeders should have access to at least the phenotypic history of
   dogs in the lines that produced the prospective mates. Having this
   information would help breeders to reduce the probability of the
   occurrence of diseases by enabling them to determine the statistical
   risks involved for propagating those diseases. The absence of this
   information means breeding with no possible way of predicting the
   outcome. It becomes a matter of pure chance.
   
   One way to make this essential information available to breeders is
   through an open registry, in which genetic diseases are recorded along
   with the information currently available in the pedigree. Today a
   stigma is often attached to a breeder and their breeding stock if this
   information is made known. Rather than sharing the information, this
   attitude leads to hiding it away. Open registries sponsored by breed
   clubs could remove this obstacle, and facilitate improved breeding
   programs. While not perfect, it can certainly help to reduce the
   problem, and it is within the reach and capabilities of everyone
   today.
     _________________________________________________________________
                                      
Preregistration Testing

   Testing of animals could be required before they are accepted by
   registration organizations. Ideally, registration would automatically
   enhance the database of genetic information available for use in
   breeding programs. Very few registration organizations do this today.
   Registration of litters could be withheld until test results,
   histories of the parents, or both were presented to and validated by
   the organizations. Registration could also carry with it the
   requirement to monitor the ongoing health of the dog, and to report
   the appearance of genetic diseases should they occur after
   registration.
     _________________________________________________________________
                                      
Show Validation

   Participation in shows could be made dependent upon test results being
   furnished to, and being evaluated by, the sponsoring organizations.
   Once entered, judges could impose penalties on animals that were found
   to have visible characteristics related to genetic diseases, and
   forward that information to the appropriate registry.
     _________________________________________________________________
                                      
Modification of Breed Standards

   All breed standards are, in effect, artificial. They have been
   developed by selectively breeding dogs over the years until they
   display a certain set of desired characteristics. Sanctioning bodies
   have procedures by which they can change the standards for various
   reasons.
   
   Physical conformation should be secondary to the health and
   temperament of an animal. If genetic diseases are associated with
   conformance characteristics in an inseparable way, breed standards
   could be modified to eliminate the incentive for breeding to those
   characteristics once the underlying association has been identified.
   In England, through a cooperative effort between the UKC and
   veterinary organizations, standards that created a propensity for
   disease have been eliminated from all breeds. The Council of Europe
   has also enacted resolutions that address the elimination of genetic
   diseases in dogs.
     _________________________________________________________________
                                      
Registration Organizations

   Registration Organizations
   
   Several organizations throughout the world register purebred dogs. In
   general, their charters are similar, and they share the common goal of
   preserving the integrity of purebred dog breeds. There are clubs that
   sanction various forms of competition, and others that deal solely
   with medical issues. Some of the oldest, largest, and most familiar
   include:
   
   The American Kennel Club (AKC) -- Founded in 1884, it is the oldest
   and most prestigious dog registration organization. The AKC includes
   in its mission: maintaining and preserving the integrity of a registry
   for purebred dogs; sanctioning of dog events that promote interest in,
   and sustain the process of, breeding for type and function of purebred
   dogs; and taking whatever actions are necessary to protect and assure
   the continuation of the sport of purebred dogs. These activities are
   undertaken with the objective of advancing the study, breeding,
   exhibiting, running, and maintenance of purebred dogs
   
   The United Kennel Club (UKC) -- The UKC was formed in 1898, and today
   provides an alternative to the more widely known AKC in the United
   States. It performs many of the same functions: registry, shows, and
   stud books. The UKC recognizes 212 breeds, including some that the AKC
   does not. The UKC offers breed, obedience, agility, and hunting
   trials.
     _________________________________________________________________
                                      
Health Related Organizations

   These are some of the organizations working on canine medical issues:
   
   Institute for Genetic Disease Control in Animals (GDC) -- In an open
   registry such as the one maintained by GDC, owners, breeders,
   scientists, and veterinarians can trace the genetic history of any
   particular dog. In order to control the increasing presence of genetic
   diseases, we must know how prevalent such diseases are in the breed
   and in any particular dog's bloodlines. The information about each dog
   automatically becomes linked in the open registry with their
   relatives. An open registry offers this information for the selection
   of mates whose bloodlines indicate a reduced risk of producing genetic
   disease.
   
   The Orthopaedic Foundation for Animals (OFA) -- This organization
   specializes in examining and rating dogs with specific regard to hip
   dysplasia.
   
   The Canine Eye Registration Foundation (CERF) -- An organization
   dealing with canine diseases of the eyes.
   
   Other organizations have embarked upon research and education programs
   related to health and genetic diseases in specific breeds. Of all AKC
   registered breed clubs, nearly three quarters have committees to
   address health concerns in their breeds. Nearly half have a code of
   ethics that includes health issues. Many breed clubs have either
   formed or are investigating the formation of tax exempt foundations to
   pursue health issues within their breeds.
   
   Among the organizations implementing such health related programs are:
   
   The Scottish Terrier Club of America (S.T.C.A.) Health Trust Fund,
   which was founded in 1994 to detect and investigate health problems;
   monitor health in Scottish Terriers; participate in research to
   enhance the prevention of illness; develop and advocate sound breeding
   practices; foster safe and healthy environments; study and share
   information that promotes better health in all purebred dogs; and
   promote and encourage constructive attitudes toward health concerns.
   In addition, membership in the S.T.C.A. requires that a Code of Ethics
   be signed which supports the issue of genetic disease elimination in
   the breed.
   
   The Cairn Terrier Club of America (CTCA). Their Committee for Health
   Related Concerns surveyed club members in 1987 for the purpose of
   determining the presence and frequency of genetic diseases in the
   breed. They have subsequently carried out an intensive education
   program, engaged the Institute for Genetic Disease Control to provide
   their open registry, and produced an award winning reference manual on
   Cairn Terrier genetic diseases.
   
   The West Highland Anomaly Task Council, Inc. (WatcH), which was Formed
   in the late 1980s for the purpose of understanding and controlling
   genetic diseases in West Highland White Terriers. WatcH has undertaken
   programs for education, information sharing, genetic counseling, and
   research. They have conducted health surveys among the WHWT
   population, and created a registry to track several genetic anomalies
   in Westies.
   
   The Jack Russell Terrier Club of America (JRTCA). Unlike other
   registries which register entire litters at birth, each JRT
   application for registration is judged on the individual terrier's own
   merits. Having registered parents does not automatically guarantee
   that a terrier can be registered. A terrier is not eligible for
   registration until it reaches one year of age and has attained its
   adult height, dentition, and other aspects considered necessary for
   full maturity. Each terrier's application for registration must be
   accompanied several documents, including a veterinary certificate, a
   four generation pedigree, a stud service certificate, and color
   photographs which support the conformation of the dogs to the club
   standard.
   
   Many projects are underway around the world in the fight against
   genetic diseases in dogs. The approach taken by organizations varies
   -- some are doing scientific research while others are providing
   education. Here is a sampling of some of these groups:
   
   The Dog Genome Project -- The dog genome project is attempting to map
   the entire genetic makeup of the domestic dog (there is a similar
   project underway for humans). The result will be a useful tool for the
   entire scientific community for the purpose of isolating the genes
   causing inherited diseases. It is a collaborative study involving
   scientists at the University of California, the University of Oregon,
   and the Fred Hutchinson Cancer Research Center. The dog genome project
   makes all research results available to the scientific community
   electronically on the World-Wide Web prior to traditional publication.
   
   Project TEACH of the Pet Health Initiative -- Project TEACH (Training
   and Education in Animal Care and Health) was formed to educate about
   proper animal care and methods of genetic screening. Project TEACH is
   an accreditation program for individuals. All TEACH-accredited
   breeders, pet shops, rescue organizations and humane societies will
   screen animals for potential problems before they are sold.
   
   AKC Canine Health Foundation -- Established by the AKC in 1995 with a
   million dollar endowment. The Foundation is intended to raise money to
   support health research which will benefit dogs, and will identify
   areas for research and seek qualified individuals to do the research
   through its Scientific Advisory committee, concerned fanciers, the
   Delegate Committee on Health Research and Health Education, and
   others. Since the early 1980's, AKC has been a major funder of genetic
   research to benefit dogs. The AKC was the principal funder of the work
   of Dr. Donald Patterson at the University of Pennsylvania to develop
   the Canine Genetic Disease Information System, a database for
   veterinarians.
   
   Better Companion Breeders Association (BCBA) - Formerly the Better Dog
   Breeders Association (B.D.B.A.). A public service agency devoted to
   the protection of the buying public. They provide their service free
   to the public, while providing members with special services to assist
   them in operating their business.
     _________________________________________________________________
                                      
Conclusion

   A concerted effort is required by everyone involved with purebred dogs
   if genetic diseases are to be eliminated. Science is making progress,
   but the time and expense required for the research point toward this
   being a long term solution. In the short term, the situation must be
   addressed using the tools at hand. Open registries for purebred dogs,
   administered by their respective breed clubs or independent registry
   organizations, appear to be the easiest and fastest way to a short
   term solution. They could also provide valuable corroborative
   information to genetic disease researchers. Cooperation between dog
   breeders, researchers, prospective purchasers, and purebred dog
   organizations at all levels is essential if genetically healthy dogs
   are to become a reality.
   
   One thing is certain -- without the continued attention of many
   people, the situation can only get worse.
     _________________________________________________________________
                                      
Selected References

     Clark, Ross D. and Joan R. Stainer, eds., "Medical and Genetic
   Aspects of Purebred Dogs", Veterinary Medicine Publishing Co.,
   Edwardsville, KA., 1983. ISBN 0-935078-24-X.
   
     Heshammer, A., and Olsson, S-E., et al, "Study of heritability in
   401 litters of German Shepherd Dogs"; J. AM Vet Med Assoc 174:
   1012-1016, 1979.
   
     Hutt, F.B., "Genetic selection to reduce the incidence of hip
   dysplasia in dogs"; J Am Vet Med Assoc; 151: 1041-1048, 1967.
   
     Lemonick MD, "A terrible beauty: An obsessive focus on show-ring
   looks is crippling, sometimes fatally, America's purebred dogs", Time
   Mag. Dec 12, 1994 :65-70
   
     Meyers, K., Wardrop, K.J., and Meinkoth, J., " Canine vWD:
   Pathobiology, diagnosis, and short-term treatment", Compendium on
   Continuing Education for the Practicing Veterinarian, 1992, Vol 14(1),
   pp.13-23.
   
     Nicholas, F.W., "Veterinary Genetics", Oxford University Press, New
   York, NY, 1987.
   
     Shook, L., "The Puppy Report: How to Select a Healthy, Happy Dog",
   Ballantine Books, New York, 1992, ISBN: 1-55821-140-3.
   
     Stokol, T. & Parry, B.W., "Canine von Willebrand Disease: a review",
   Aust. Vet. Practit. 23 (2), June, 1993. pp. 94 - 103. Willis, Malcolm
   B. "Practical Genetics for Dog Breeders", Howell Book House, NYC, 1992
   and H. F. & G. Witherby Ltd., UK, 1992.
   
     Willis, Malcolm B. "The Genetics of the Dog" Howell Book House, NYC,
   1989 and H. F. & G. Witherby Ltd., UK, 1989.
     _________________________________________________________________
                                      
   
    Eliminating Genetic Diseases in Dogs: A Buyer's Perspective
    Copyright 1995 Gary F. Mason. All rights reserved.
    Gary F. Mason, gmason@ileaf.com.
    Reproduced with permission.
    
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